arXiv papers from July 1993

Sergio Caracciolo, Robert G. Edwards, Andrea Pelissetto, Alan D. Sokal

We argue that the two-dimensional $O(N)$-invariant lattice $\sigma$-model with mixed isovector/isotensor action has a one-parameter family of nontrivial continuum limits, only one of which is the continuum $\sigma$-model constructed by conventional perturbation theory. We test the proposed scenario with a high-precision Monte Carlo simulation for $N=3,4$ on

S. Lukyanov

A new approach to massive integrable models is considered. It allows one to find symmetry algebras which define spaces of local operators and to get general integral representations for form-factors in the\ $ SU(2)$\ Thirring and Sine-Gordon models.

G. Marchesini

Results presented in perturbative QCD are reviewed. The topics discussed include: - struction functions, - heavy flavour production, - direct photon production, - inclusive production at LHC/SSC, - small $x$ physics, - QCD jets and - intermittency. For reference to the data in this talk see the summary presented by J.E. Augustin.

G. Marchesini

A brief summary is given of some recent perturbative QCD results on the evaluation of cross sections and on the the structure of final states in processes with incoming hadrons at small $x$. A new Monte Carlo simulation which includes these theoretical features is described together with its applications to the study of heavy quark production in $ep$ collisi

D. Sorokin, M. Tonin

An n=8 worldsheet superfield action is proposed for describing chiral fermions in the twistor-like formulation of an N=1, D=10 heterotic superstring.

Todd A. Brun

Using the decoherence formalism of Gell-Mann and Hartle, a quantum system is found which is the equivalent of the classical chaotic Duffing oscillator. The similarities and the differences from the classical oscillator are examined; in particular, a new concept of quantum maps is introduced, and alterations in the classical strange attractor due to the prese

V. Bach, E. H. Lieb, M. Loss, J. P. Solovej

Hartree-Fock theory is supposed to yield a picture of atomic shells which may or may not be filled according to the atom's position in the periodic table. We prove that shells are always completely filled in an exact Hartree-Fock calculation. Our theorem generalizes to any system having a two-body interaction that, like the Coulomb potential, is repulsive.

C. M. Kormanyos, R. J. Peterson, J. R. Shepard, J. E. Wise

K$^+$--nucleus quasielastic cross sections measured for a laboratory kaon beam momentum of 705 MeV/$c$ are presented for 3--momentum transfers of 300 and 500 MeV/$c$. The measured differential cross sections for C, Ca and Pb at 500 MeV/$c$ are used to deduce the effective number of nucleons participating in the scattering, which are compared with estimates b

W. A. Bardeen, C. T. Hill, D. -U. Jungnickel

A wide class of models involve the fine--tuning of significant hierarchies between a strong--coupling ``compositeness'' scale, and a low energy dynamical symmetry breaking scale. We examine the issue of whether such hierarchies are generally endangered by Coleman--Weinberg instabilities. A careful study using perturbative two--loop renormalization group meth

Matt Visser

It is by now clear that the naive rule for the entropy of a black hole, {entropy} = 1/4 {area of event horizon}, is violated in many interesting cases. Indeed, several authors have recently conjectured that in general the entropy of a dirty black hole might be given purely in terms of some surface integral over the event horizon of that black hole. A formal

Bijan Haeri,

A new interaction that confines the top quark at the electroweak scale is proposed to account for a top quark mass potentially close in value to the electroweak scale.

Bernardo A. Huberman, Natalie S. Glance

The prisoner's dilemma has long been considered the paradigm for studying the emergence of cooperation among selfish individuals. Because of its importance, it has been studied through computer experiments as well as in the laboratory and by analytical means. However, there are important differences between the way a system composed of many interacting eleme

Victor V. Batyrev, Duco van Straten

We formulate general conjectures about the relationship between the A-model connection on the cohomology of a $d$-dimensional Calabi-Yau complete intersection $V$ of $r$ hypersurfaces $V_1, \ldots, V_r$ in a toric variety ${\bf P}_{\Sigma}$ and the system of differential operators annihilating the special hypergeometric function $\Phi_0$ depending on the fan

J. -M. Frère, M. Tytgat, J. M. Moreno, J. Orloff

In this note we expand on our previous study of the implications of LEP1 results for future colliders. We extend the effective operator-based analysis of De R\'ujula et al. to a larger symmetry group, and show at which cost their expectations can be relaxed. Of particular interest to experiment is a rephrasing of our previous results in terms of the Renard e

B. Basu-Mallick

By considering `coloured' braid group representation we have obtained a quantum group, which reduces to the standard $GL_q(2)$ and $GL_{p,q}(2)$ cases at some particular limits of the `colour' parameters. In spite of quite complicated nature, all of these new quantum group relations can be expressed neatly in the Heisenberg-Weyl form, for a nontrivial choice

Roger Decker, Markus Finkemeier

We have calculated the O(alpha) radiative corrections to the tau decay tau -> pi (K) nu, taking into account both the point meson contribution and the structure dependent radiation. We find for the ratio Gamma(tau -> pi nu (gamma)) / Gamma(pi -> mu nu (gamma)) a radiative correction of + 1.2% and for Gamma(tau -> K nu (gamma)) / Gamma(K -> mu nu (gamma)) one

Masaru Onoda

We study the U(1) Higgs model in spacetime-dependent background fields (a background metric and a background scalar field). Particle creation can occur because of the time-dependence of these background fields. In gauge theories, there is a unphysical sector and consequently unphysical particles may be produced. However, it is shown that produced unphysical

Mark Hindmarsh

The Cosmic Microwave Background (CMB) fluctuations at very small angular scales (less than $10'$) induced by matter sources are computed in a simplified way. The result corrects a previous formula appearing in the literature. The small scale power spectrum from cosmic strings is then calculated by a new analytic method. The result compares extremely well wit

A. I. Davydychev, V. A. Smirnov, J. B. Tausk

For two-loop two-point diagrams with arbitrary masses, an algorithm to derive the asymptotic expansion at large external momentum squared is constructed. By using a general theorem on asymptotic expansions of Feynman diagrams, the coefficients of the expansion are calculated analytically. For some two-loop diagrams occurring in the Standard Model, comparison

M. Crivelli, Giovanni Felder, C. Wieczerkowski

We compute the mapping class group action on cycles on the configuration space of the torus with one puncture, with coefficients in a local system arising in conformal field theory. This action commutes with the topological action of the quantum group $U_q(sl_2)$, and is given in vertex form.

L. Feher, L. O'Raifeartaigh, I. Tsutsui

We simplify and generalize an argument due to Bowcock and Watts showing that one can associate a finite Lie algebra (the `classical vacuum preserving algebra') containing the M\"obius $sl(2)$ subalgebra to any classical $\W$-algebra. Our construction is based on a kinematical analysis of the Poisson brackets of quasi-primary fields. In the case of the $\W_\S

K. Ito, J. O. Madsen, J. L. Petersen

We develop the method of the hamiltonian reduction of affine Lie superalgebras to obtain explicit and general expressions both for the classical and the quantum extended superconformal algebras. By performing the gauge transformation which connects the diagonal gauge with the Drinfeld-Sokolov gauge and considering the quantum corrections, we get generic expr

Deog Ki Hong

We study how the Chern-Simons term effects the dynamically generated fermion mass in $(2+1)D$ Quantum Electrodynamics in the framework of large $N$ expansion. We find that when the Chern-Simons term is present half of the fermions get mass $M+m$ and half get $M-m$. The parity-preserving mass $m$ is generated only when $N<\tilde{N}_c$. Both the critical numbe

D. K. Hong, S. H. Park

We analyze $(2+1)$-dimensional vector-vector type four-Fermi interaction (Thirring) model in the framework of the $1/N$ expansion. By solving the Dyson-Schwinger equation in the large-$N$ limit, we show that in the two-component formalism the fermions acquire parity-violating mass dynamically in the range of the dimensionless coupling $\alpha$, $0 \leq \alph

Tohru Eguchi

We discuss the properties of the Liouville theory coupled to the c=1 matter when perturbed by an operator, the screening operator of the $SL(2;R)$ current algebra, which is supposed to generate the mass of the two-dimensional black hole. Mimicking the standard KPZ scaling theory of the Liouville system perturbed by the cosmological constant operator, we deve

A. J. Davies, T. Hayashi, M. Matsuda, M. Tanimoto

We systematically analyse the gluonic penguin-induced charmless decays $B \ra K_X\phi$($K_X$ denotes the meson state $s\bar q \;(q=u\ {\rm or}\ d)$ ), in the standard model and the two-Higgs-doublet model. These processes, being induced at one-loop level, are of great importance in measuring the virtual top quark effect in the standard model, and also in sea

G. Q. Li, R. Machleidt

We derive in-medium nucleon-nucleon (NN) cross sections in a microscopic model. Our calculations are based upon the Bonn NN potential and the Dirac-Brueckner approach for nuclear matter. We consider energies up to 300 MeV (in the laboratory frame) and densities up to twice nuclear matter density. Our results deviate substantially from cross section parametri

G. Baillie

We examine the prospects for observing weak flavour-changing neutral current (FCNC) decays of \B\ mesons at hadron colliders, including effects of anomalous $WWZ$~vertices. Since it is very difficult to measure the inclusive rate $B \rightarrow X_s \, \lp \lm$ one should consider exclusive modes such as \BKsmumu\ and \BKmumu. Even though this requires one to

Kai Nagel, Hans J. Herrmann

We study several deterministic one-dimensional traffic models. For integer positions and velocities we find the typical high and low density phases separated by a simple transition. If positions and velocities are continuous variables the model shows self-organized criticality driven by the slowest car.

Bob Bailey, Dirk Graudenz

Using next-to-leading-log calculations of Higgs production and hadronic two photon production, a signal and background study in the intermediate mass range of the Higgs boson is done for $\sqrt{s}=$ 40 and 14 TeV. The effects of realistic cuts, including photon isolation, are examined.

Stefan V. Mashkevich

The general notion of distance dependent statistics in anyon-like systems is discussed. The two-body problem for such statistics is considered, the general formula for the second virial coefficient is derived and it is shown that in the limiting cases it reproduces the known results for ideal anyons.

E. Granato

A generalization of the one-dimensional frustrated quantum XY model is considered in which the inter and intra-chain coupling constants of the two infinite XY (planar rotor) chains have different strengths. The model can describe the superconductor to insulator transition due to charging effects in a ladder of Josephson junctions in a magnetic field with hal

Qimiao Si

We summarize our recent theoretical studies on the spin dynamics in the normal state of the metallic cuprates. The contrasting wave vector dependence of the dynamical spin structure factor $S({\bf q}, \omega )$ in LaSrCuO and YBaCuO systems are attributed to the differences in the fermiology, in conjunction with strong Coulomb correlations. These effects are

Gabriel Kotliar, Qimiao Si

We formulate a local picture of strongly correlated systems as a Feynman sum over atomic configurations. The hopping amplitudes between these atomic configurations are identified as the renormalization group charges, which describe the local physics at different energy scales. For a metallic system away from half-filling, the fixed point local Hamiltonian is

Qimiao Si, Gabriel Kotliar

We study an extended Hubbard model in the limit of infinite dimensions and its zero dimensional counterpart, a generalized asymmetric Anderson model. In the impurity model we find three kinds of mixed valence states: a) the usual strong coupling state in which a resonance forms at the Fermi level; b) a weak coupling state in which neither the impurity spin n

J. F. Gunion

I review recent developments in the theory and phenomenology of Higgs bosons at an $\epem$ linear collider with $\sqrt s$ of order 500 GeV.

Saurya Das, Parthasarathi Majumdar

The amplitude for the scattering of a point magnetic monopole and a point charge, at centre-of-mass energies much larger than the masses of the particles, and in the limit of low momentum transfer, is shown to be proportional to the (integer-valued) monopole strength, assuming the Dirac quantization condition for the monopole-charge system. It is demonstrate

M. Ciuchini, E. Franco, G. Martinelli, L. Reina

We present a calculation of the effective weak Hamiltonian which governs $b \rightarrow s\, \gamma$ and $b \rightarrow s \, g$ transitions in two different renormalization schemes (NDR and HV). In the leading logarithmic approximation, we show that the coefficients of the effective Hamiltonian are scheme independent only when one takes correctly into account

Masako Bando, Masayasu Harada

We investigate the properties of the amplitude induced by the anomaly. In a relatively high energy region those amplitudes are constructed by the vector meson poles and the anomaly terms, in which the anomaly terms can be essentially evaluated by the triangle quark graph. We pay our attention to the anomaly term and make intensive analysis of the existing ex

Masako Bando, Masayasu Harada

We propose an interpolating formula for the amplitude induced by the axial anomaly, concentrating on the $\pi^0\gamma^{\ast}\gamma^{\ast}$ transition form factor. The QCD corrections to this amplitude are generally described by two major contributions coming from the $q\bar{q}$ bound state and the background continuous spectrum, respectively. For the first c

Robert M. Wald

We consider a general, classical theory of gravity in $n$ dimensions, arising from a diffeomorphism invariant Lagrangian. In any such theory, to each vector field, $\xi^a$, on spacetime one can associate a local symmetry and, hence, a Noether current $(n-1)$-form, ${\bf j}$, and (for solutions to the field equations) a Noether charge $(n-2)$-form, ${\bf Q}$.

Eyal Maoz

If gamma-ray bursts originate at cosmological distances then their angular distribution should exhibit a dipole in the direction of the solar motion relative to the cosmic microwave background. This is due to the combined effects of abberation, an anisotropic shift of the burst event rate, and an angular variation in the distance out to which bursts can be d

F. David, B. Duplantier, E. Guitter

The renormalizability of the self-avoiding manifold (SAM) Edwards model is established. We use a new short distance multilocal operator product expansion (MOPE), which extends methods of local field theories to a large class of models with non-local singular interactions. This validates the direct renormalization method introduced before, as well as scaling

M. Gaberdiel

Following a recent proposal of Richard Borcherds to regard fusion as the ring-like tensor product of modules of a {\em quantum ring}, a generalization of rings and vertex operators, we define fusion as a certain quotient of the (vector space) tensor product of representations of the symmetry algebra ${\cal A}$. We prove that this tensor product is associativ

Charles Gale, Peter Lichard

We study the net dielectron production rates from an ensemble of thermal mesons, using an effective Lagrangian to model their interaction. The coupling between the electromagnetic and the hadronic sectors is done through the vector meson dominance approach. For the first time, a complete set of light mesons is considered. We include contributions from decays

R. Baier, A. Niegawa

We consider thermal $n$-point Green functions in the framework of quantum field theory at finite temperature. We show how analytic continuations from imaginary to real energies relate these functions originally defined in the imaginary-time formalism to retarded and advanced real-time ones. The described method is valid to all orders of perturbation theory.

M. Hotta, M. Yoshimura

It is shown in a variant of two dimensional dilaton gravity theories that an arbitrary, localized massive source put in an initially regular spacetime gives rise to formation of the wormhole classically, without accompanying the curvature singularity. The semiclassical quantum correction under this wormhole spacetime yields Hawking radiation. It is expected,

Tao Han

If there are no light Higgs bosons found below $\cal O$(800 GeV) or so, the interactions among longitudinally-polarized vector bosons ($\wl$) will become strong at the TeV region, and new physics that is responsible for the electroweak symmetry breaking must emerge at this energy scale. We discuss the phenomenological prospects of the Strongly-interacting El

A. Nusser, A. Dekel, A. Yahil

We recover the one-point probability distribution function of the {\it initial} density fluctuations (\ipdf) from the quasi-linear galaxy density field of the 1.2 Jy \iras\ redshift survey smoothed by $10\hmpc$. The recovery, using the laminar, Eulerian, Zel'dovich approximation of Nusser and Dekel, is independent of $\Omega$ and is relatively insensitive to

B. K. Chung, Soonkeon Nam, Q-Han Park, H. J. Shin

We investigate various boundary conditions in two dimensional turbulence systematically in the context of conformal field theory. Keeping the conformal invariance, we can either change the shape of boundaries through finite conformal transformations, or insert boundary operators so as to handle more general cases. Effects of such operations will be reflected

Daniel Armand-Ugon, Rodolfo Gambini, Jorge Griego, Leonardo Setaro

Since the first attempts to quantize Gauge Theories and Gravity in the loop representation, the problem of the determination of the corresponding classical actions has been raised. Here we propose a general procedure to determine these actions and we explicitly apply it in the case of electromagnetism. Going to the lattice we show that the electromagnetic ac

Taejin Lee, Phillial Oh

We present a new method of formulating the classical theory of $SU(N+1)$ non-Abelian Chern-Simons (NACS) particles for arbitrary $N\geq 1$ using the symplectic reduction of $CP(N)$ manifold from $S^{2N+1}$. Quantizing the theory using BRST formulation and coherent state path integral method , we obtain a quantum mechanical model for $SU(N+1)$ NACS particles.

A. Yu. Ignatiev, G. C. Joshi

We present the limits on possible time variation of the electric charges of quarks and leptons at the time of primordial nucleosynthesis within a model with dequantized electric charges which allows for the case of charged neutrino and neutron.

Misha Verbitsky

We prove that all complex analytic subvarieties of a generic compact hyperkaehler manifold are even-dimensional. Moreover, these subvarieties are holomorphically symplectic.

Misha Verbitsky

Hyperholomorphic bundle is a bundle with connection defined over a hyperkaehler manifold such that this connection is holomorphic with respect to all complex structures induced by a hyperkaehler structure. A hyperholomorphic connection is Yang-Mills. If a stable bundle has first two Chern classes invariant with respect to ${\Bbb H}$, then it admits a hyperho

Felix Ritort

The nature of static chaos in Ising spin glasses is studied. For the problem of chaos with magnetic field, scaling relations in the case of the SK model and short-range models are presented. Our results also suggest that if there is de Almeida-Thouless line then it is similar to that of mean-field theory for d=4 and close to the h=0 axis for d=3. We estimate

James H. Horne, Gary T. Horowitz

We investigate extremal electrically charged black holes in Einstein-Maxwell-dilaton theory with a cosmological constant inspired by string theory. These solutions are not static, and a timelike singularity eventually appears which is not surrounded by an event horizon. This suggests that cosmic censorship may be violated in this theory.

Sergio Caracciolo, Andrea Pelissetto, Alan D. Sokal

We prove that for any Monte Carlo algorithm of Metropolis type, the autocorrelation time of a suitable ``energy''-like observable is bounded below by a multiple of the corresponding ``specific heat''. This bound does not depend on whether the proposed moves are local or non-local; it depends only on the distance between the desired probability distribution $

Marek Jeżabek, Johann H. Kühn, Thomas Teubner

Calculations of radiative corrections to the top quark width are reviewed. QCD effects are discussed for $t-\bar t$ systems produced in $e^+e^-$ annihilation near the energy threshold.}

M. Jeżabek, C. Jünger

A relatively simple analytical formula is derived for the energy spectrum of $W$ boson in top quark decays $t\to Wb$ including ${\cal O}(\alpha_s)$ radiative corrections. We discuss the accuracy of this formula and compare it to a more general albeit more complicated one derived in \cite{CJK}~. A Monte Carlo algorithm for generation of $W$ energy spectrum is

B. Holdom

Cosmic balloons, consisting of relativistic particles trapped inside a spherical domain wall, may be created in the early universe. We calculate the balloon mass $M$ as a function of the radius $R$ and the energy density profile, $\rho (r)$, including the effects of gravity. At the maximum balloon mass $2GM/R\approx 0.52$ for any value of the mass density of

J. M. Isidro, A. V. Ramallo

Two-dimensional topological field theories possessing a non-abelian current symmetry are constructed. The topological conformal algebra of these models is analysed. It differs from the one obtained by twisting the $N=2$ superconformal models and contains generators of dimensions $1$, $2$ and $3$ that close a linear algebra. Our construction can be carried ou

David Hochberg, Thomas W. Kephart, James W. York,

Expectation values of one-loop renormalized thermal equilibrium stress-energy tensors of free conformal scalars, spin-${1 \over 2}$ fermions and U(1) gauge fields on a Schwarzschild black hole background are used as sources in the semi-classical Einstein equation. The back-reaction and new equilibrium metric are solved for at $O({\hbar})$ for each spin field

D. Diakonov, V. Petrov

We use singular Euclidean solutions to find multi-particle production cross sections in field theories. We investigate a family of time-dependent O(3) symmetrical solutions of the Yang--Mills equations, which govern the isotropic high-energy gauge boson production. At low energies our approach reproduces the instanton-induced cross sections. For higher energ

Z. Zhu, D. G. Caldi

Hirota's method is used to construct multi--soliton and plane--wave solutions for affine Toda field theories with imaginary coupling.

M. Bonini, M. D'Attanasio, G. Marchesini

We analyze a formulation of QED based on the Wilson renormalization group. Although the ``effective Lagrangian'' used at any given scale does not have simple gauge symmetry, we show that the resulting renormalized Green's functions correctly satisfies Ward identities to all orders in perturbation theory. The loop expansion is obtained by solving iteratively

C. R. Münz, J. Resag, B. C. Metsch, H. R. Petry

The spectra and electroweak decay properties of light mesons are analyzed within the framework of the instantaneous Bethe-Salpeter equation. The interaction kernel comprises alternative spin-structures for a parameterization of confinement and a residual quark-antiquark interaction based on instanton effects. It is shown that only with a vector confinement t

J. Resag, C. R. Münz, B. C. Metsch, H. R. Petry

We investigate the structure of the instantaneous Bethe-Salpeter equation for \(q\bar{q}\)-bound states in the general case of unequal quark masses and develop a numerical scheme for the calculation of mass spectra and Bethe-Salpeter amplitudes. In order to appreciate the merits of the various competing models beyond the reproduction of the mass spectra we p

U. Baur, S. Errede, G. Landsberg

We study the correlation of photon and charged lepton pseudorapidities, $\eta(\gamma)$ and $\eta(\ell)$, $\ell=e,\,\mu$, in $p\bar p\rightarrow W^\pm\gamma+X\rightarrow \ell^\pm p\llap/_T\gamma+X$ at the Tevatron. In the Standard Model, the $\Delta\eta(\gamma,\ell)= \eta(\gamma) - \eta(\ell)$ differential cross section is found to exhibit a pronounced dip at

Stefano Panzeri

We find the exact matrix model description of two dimensional Yang-Mills theories on a cylinder or on a torus and with an arbitrary compact gauge group. This matrix model is the singlet sector of a $c =1$ matrix model where the matrix field is in the fundamental representation of the gauge group. We also prove that the basic constituents of the theory are Su

D. Bailin, A. Love, W. A. Sabra

We study the Yukawa couplings among excited twist fields which might arise in the low-energy effective field theory obtained by compactifying the heterotic string on ${\bf Z}_N$ and ${\bf Z}_M\times {\bf Z}_N$ orbifolds.

Stephen F. King

Using a combination of renormalisation group and effective potential methods, we discuss the bound on the lightest CP-even Higgs boson mass $m_h$ in the next-to-minimal supersymmetric standard model. We find $m_h\leq 146,139,149 \ GeV$ for $m_t=90,140,190 \ GeV$.

J. Cleymans, S. V. Ilyun, S. A. Smolyansky, G. M. Zinovjev

The temperature dependence of the kinetic coefficients is obtained in the non-perturbative region with the help of Green-Kubo-type formulae in the model of massive gluon gas motivated by numerical results from simulations of lattice QCD. The entropy production rate is estimated using scaling hydrodynamics. It is shown that the increase in the viscosity coeff

J. Cleymans, I. Dadic, J. Joubert

Deep inelastic scattering is considered in a statistical model of the nucleon. This incorporates certain features which are absent in the standard parton model such as quantum statistical correlations which play a role in the propagation of particles when considering Feynman diagrams containing internal lines. The inclusion of the ${\cal O}(\alpha_{s})$ corr

N. Bilic, J. Cleymans, K. Redlich, E. Suhonen

The effect of a sharp front separating the quark-gluon plasma phase from the hadronic phase is investigated. Energy-momentum conservation and baryon number conservation constrain the possible temperature jump across the front. If one assumes that the temperature in the hadronic phase is $T\simeq$ 200 MeV , as has been suggested by numerous results from relat

P. Mayr, H. P. Nilles, S. Stieberger

The interpretation of the apparent unification of gauge couplings within supersymmetric theories depends on uncertainties induced through heavy particle thresholds. While in standard grand unified theories these effects can be estimated easily, the corresponding calculations are quite complicated in string unified theories and do exist only in models with un

S. P. Sorella, L. Tataru

The new method for solving the descent equations for gauge theories proposed in \cite{s} is shown to be equivalent with that based on the {\em "Russian formula"}. Moreover it allows to obtain in a closed form the expressions of the consistent anomalies in any space-time dimension.

K. Hornfeck

We show that the structure constants of W-algebras can be grouped according to the lowest (bosonic) spin(s) of the algebra. The structure constants in each group are described by a unique formula, depending on a functional parameter h(c) that is characteristic for each algebra. As examples we give the structure constants C_{33}^4 and C_{44}^4 for the algebra

Andrea Ferrara, George B. Field

We present a study of the ionization and thermal structure of neutral hydrogen clouds located in the Galactic halo, immersed in the extragalactic background radiation field, and supposed to be in pressure equilibrium with the surrounding (presumably) hot medium. The problem is solved numerically, but an useful analytical approximation has been derived as wel

Yoshiki Kizukuri, Noriyuki Oshimo

We discuss the possibility of observing $CP$ violation predicted by the supersymmetric standard model.

Alan D. Sokal

I make three conceptual points regarding multigrid methods for computing propagators in lattice gauge theory: 1) The class of operators handled by the algorithm must be stable under coarsening. 2) Problems related by symmetry should have solution methods related by symmetry. 3) It is crucial to distinguish the vector space $V$ from its dual space $V^*$. All

Huazhong Zhang

We study some topological aspects of non-abelian gauge theories intimately connected to the Lie algebras of the gauge groups and the homotopy theory in the generalized gauge orbit space. The physics connection to the non-perturbative solution to strong CP problem as originally proposed by the author is also discussed. Some relevant topological formulas are a

Kikuo Harigaya, G. A. Gehring

An elastic anomaly, observed in the heavy Fermi liquid state of Ce alloys (for example, CeCu_6 and CeTe), is analyzed by using the infinite-U Anderson lattice model. Four atomic energy levels are assumed for f-electrons. Two of them are mutually degenerate. A small crystalline splitting 2 Delta is assumed between two energy levels. Fourfold degenerate conduc

M. Kasner, W. Apel

The various proposals for FQHE quasi-electron trial wave functions are reconsidered. In a short-range model for the electronic interaction, the energy expectation values of four different trial wave functions are calculated at filling factor $\frac{1}{3}$ for up to ten electrons in the disk geometry. Jain&#39;s trial wave function displays the lowest energy

Bernardo Huberman, Natalie Glance

We elucidate the dynamics of ongoing collective action among intentional agents with diverse beliefs and imperfect information. Their decisions on whether or not to contribute to the collective good depend not only on the past but also on their expectations as to how their actions will affect those of others. We show that in attempts at collective action the

Raju Venugopalan, Axel Vischer

We compute the dynamical prefactor in the nucleation rate of bubbles or droplets in first order phase transitions for the case where both viscous damping and thermal dissipation are significant. This result, which generalizes previous work on nucleation, may be applied to study the growth of bubbles or droplets in condensed matter systems as well as in heavy

Howard Baer, Chung Kao, Xerxes Tata

We have used ISAJET 7.0/ISASUSY 1.0 to evaluate the rates and study distributions for trilepton events from the leptonic decays of charginos and neutralinos produced at the Fermilab Tevatron via the reaction, $p\bar p\rightarrow \tilde{W_1} \tilde{Z_2}$ + X for cuts inspired by the CDF and D0 experiments. We find that about 60\% of these events do not contai

Natalie Glance, Bernardo Huberman

We show that fluid organizations display higher levels of cooperation than attainable by groups with either a fixed social structure or lacking one altogether. By moving within the organization, individuals cause restructurings that facilitate cooperation. Computer experiments simulating fluid organizations faced with a social dilemma reveal a myriad of comp

Ying-Hong Li, S. Teitel

Monte Carlo simulations of the uniformly frustrated 3d XY model are used to model vortex line fluctuations in high temperature superconductors in an applied magnetic field. We find two distinct phase transitions. At a lower T_{c\perp}, the vortex lattice melts and coherence is lost in planes perpendicular to the magnetic field. At a higher T_{cz}, a vortex t

D. M. Deaven, D. S. Rokhsar, A. Barbieri

We study Gutzwiller-projected variational wavefunctions for charged, spinless holon excitations in chiral spin liquids. We find that these states describe anyons, with a statistical phase $\Phi_s$ that is continuously adjustable between $0$ and $\pi/2$, depending on a variational parameter. The statistical flux attached to each holon is localized to within a

W. D. Garretson, E. D. Carlson

There is increasing evidence that the universe may have a small cosmological constant. We suggest a scheme for naturally generating a small cosmological constant. Our idea requires the presence of a discrete accidental symmetry which is spontaneously broken by vacuum expectation values of the fields, and explicitly broken by high dimensional operators in the

Alexander Kusenko, Robert Shrock

We present a simple model for fermion mass matrices and quark mixing in the context of supersymmetric grand unified theories and show its agreement with experiment. Our model realizes the GUT mass relations $m_d=3m_e$, $m_s= m_\mu/3$, $m_b=m_\tau$ in a new way and is easily consistent with values of $m_t$ suggested by MSSM fits to LEP data.

Peter Cho, Elizabeth Simmons

The impact of nonrenormalizable gluon operators upon inclusive jet cross sections is studied. Such operators could arise in an effective strong interaction Lagrangian from gluon substructure and would induce observable cross section deviations from pure QCD at high transverse jet energies. Comparison of the theoretical predictions with recent CDF data yields

C. Kobdaj, S. Thomas

A study is presented of classical field configurations describing nonabelian vortices in two spatial dimensions, when a global \( SO(3) \) symmetry is spontaneously broken to a discrete group \( \IK \) isomorphic to the group of integers mod 4. The vortices in this model are characterized by the nonabelian fundamental group \(\pi_1 (SO(3)/{\IK}) \), which is

A. N. Leznov, A. V. Razumov

The properties of discrete nonlinear symmetries of integrable equations are investigated. These symmetries are shown to be canonical transformations. On the basis of the considered examples, it is concluded, that the densities of the conservation laws are changed under these transformations by spatial divergencies.

R. Bönisch

The scalar interaction term of the top mode standard model can be generated by a gauge theory. It is emphasized that in this approach generalization to family space directly yields a heavy top quark while leaving all other quarks massless. By generating the new interaction from gauge extension to custodial $SU(2)$, the standard model bound $m_{top} \stackrel

Paul Fendley, Ken Intriligator

We find exactly solvable N=2-supersymmetric flows whose infrared fixed points are the N=2 minimal models. The exact S-matrices and the Casimir energy (a c-function) are determined along the entire renormalization group trajectory. The c-function runs from c=3 (asymptotically) in the UV to the N=2 minimal model values of the central charge in the IR, leading

L. Susskind

String theory provides an example of the kind of apparent inconsistency that the {\it Principle of Black Hole Complementarity\/} deals with. To a freely infalling observer a string falling through a black hole horizon appears to be a Planck size object. To an outside observer the string and all the information it carries begin to spread as the string approac

P. A. Shah, N. S. Manton

The thermodynamics of vortices in the critically coupled abelian Higgs model, defined on the plane, are investigated by placing $N$ vortices in a region of the plane with periodic boundary conditions: a torus. It is noted that the moduli space for $N$ vortices, which is the same as that of $N$ indistinguishable points on a torus, fibrates into a $CP_{N-1}$ b

Gideon Lana

We calculate the two-body interaction of spherical hadronic bubbles immersed in a gluon plasma at temperatures above the phase transition. Modeling the bubbles with the MIT bag we find that the two body potential is repulsive for all bubble-bubble distances considered. This implies that a static configuration of spherical hadronic bubbles in a gluon backgrou